BBCode in RichTextLabel

Introduction

Label nodes are great for displaying basic text, but they have limits. If you want to change the color of the text, or its alignment, that change affects all of the text in the Label node. You can't have only one part of the text be one color, or only one part of the text be centered. To get around this limitation you would use a RichTextLabel.

RichTextLabel allows the display of complex text markup in a Control. It has a built-in API for generating the markup, but can also parse a BBCode.

Note that the BBCode tags can also be used, to some extent, in the XML source of the class reference. For more information, see Class reference writing guidelines.

Using BBCode

For uniformly formatted text you can write in the "Text" property, but if you want to use BBCode markup you should use the "Text" property in the "Bb Code" section instead (bbcode_text). Writing to this property will trigger the parsing of your markup to format the text as requested. Before this happens, you need to toggle the "Enabled" checkbox in the "Bb Code" section (bbcode_enabled).

../../_images/bbcodeText.png

For example, BBCode [color=blue]blue[/color] would render the word "blue" with a blue color.

../../_images/bbcodeDemo.png

You'll notice that after writing in the BBCode "Text" property the regular "Text" property now has the text without the BBCode. While the text property will be updated by the BBCode property, you can't edit the text property or you'll lose the BBCode markup. All changes to the text must be done in the BBCode parameter.

Note

For BBCode tags such as [b] (bold), [i] (italics) or [code] to work, you must set up custom fonts for the RichTextLabel node first.

There are no BBCode tags to control vertical centering of text yet.

Reference

Command

Tag

Description

bold

[b]{text}[/b]

Makes {text} bold.

italics

[i]{text}[/i]

Makes {text} italics.

underline

[u]{text}[/u]

Makes {text} underline.

strikethrough

[s]{text}[/s]

Makes {text} strikethrough.

code

[code]{text}[/code]

Makes {text} use the code font (which is typically monospace).

p

[p {options}]{text}[/p]

Adds new paragraph with {text}. See paragraph options for more info.

center

[center]{text}[/center]

Makes {text} horizontally centered. Same as [p align=center].

left

[left]{text}[/left]

Makes {text} horizontally right-aligned. Same as [p align=left].

right

[right]{text}[/right]

Makes {text} horizontally right-aligned. Same as [p align=right].

fill

[fill]{text}[/fill]

Makes {text} fill the RichTextLabel's width. Same as [p align=fill].

indent

[indent]{text}[/indent]

Increase the indentation level of {text}.

url

[url]{url}[/url]

Show {url} as such, underline it and make it clickable.

url (ref)

[url=<url>]{text}[/url]

Makes {text} reference <url> (underlined and clickable).

image

[img]{path}[/img]

Insert image at resource {path}.

resized image

[img=<width>]{path}[/img]

Insert image at resource {path} using <width> (keeps ratio).

resized image

[img=<width>x<height>]{path}[/img]

Insert image at resource {path} using <width>×<height>.

aligned image

[img align=<valign>]{path}[/img]

Insert image at resource {path} using <valign> vertical alignment.

font

[font=<path>]{text}[/font]

Use custom font at <path> for {text}.

font options

[font {options}]{text}[/font]

Use custom font options for the {text}. See font options for more info.

font size

[font_size=nn]{text}[/font_size]

Use custom font size for {text}.

opentype features

[opentype_features=ftr,ftr]{text}[/opentype_features]

Use custom OpenType font features (comma separated list) for {text}.

outline size

[outline_size=<size>]{text}[/outline_size]

Use custom font outline size for {text}.

outline color

[outline_color=<color>]{text}[/outline_color]

Use custom outline color for {text}.

color

[color=<code/name>]{text}[/color]

Change {text} color; use name or # format, such as #ff00ff.

table

[table=<number>]{cells}[/table]

Creates a table with <number> of columns.

cell

[cell=<expand ratio>]{text}[/cell]

Adds cells with the {text} to the table.

cell

[cell {options}]{text}[/cell]

Adds cells with the {text} to the table. See cell options for more info.

list

[ul]{one item per line}[/ul]

Add unnumbered list.

list

[ol type=<type>]{one item per line}[/ol]

Add numbered list. See list types for more info.

unicode control

[lrm], [rlm], [lre], [rle], [lro], [rlo], [pdf], [alm], [lri], [rli], [fsi], [pdi], [zwj], [zwnj], [wj]

Adds Unicode control character.

Note: Options are optional for all tags.

Paragraph options

Option

Supported Values

Description

align

left, center, right, fill

Text horizontal alignment.

direction or dir

ltr, rtl, auto

Base BiDi direction.

language or lang

ISO language codes

Locale override.

bidi_override or st

default, uri, file, email, list, none, custom

Structured text override.

Font options

Option

Description

name or n

Font resource path.

size or s

Font size.

Cell options

  • expand - Column expansion ratio, the column expands in proportion to its expansion ratio versus the other columns' ratios.

  • border - Sets cell border color.

  • bg - Sets cell background color, for alternating odd/even row backgrounds use bg=odd_color,even_color.

List types

Supported list types:

  • 1 - Numbers, using language specific numbering system if possible.

  • a and A - Lower and upper case Latin letters.

  • i and I - Lower and upper case Roman numerals.

Named colors

You can use the constants of the Color class for the [color=<name>] tag. The case and style of the name is not important: DARK_RED, DarkRed and darkred will give the same result.

Hexadecimal color codes

For opaque RGB colors, any valid 6-digit hexadecimal code is supported, e.g. [color=#ffffff]white[/color].

For transparent RGB colors, any 8-digit hexadecimal code can be used, e.g. [color=#88ffffff]translucent white[/color]. In this case, note that the alpha channel is the first component of the color code, not the last one.

Image vertical offset

Use [img=align]...[/img] to set vertical alignment of the image, where align is t (top), c (center) or b (bottom).

Animation effects

BBCode can also be used to create different text animation effects. Five customizable effects are provided out of the box, and you can easily create your own.

Wave

../../_images/wave.png

Wave makes the text go up and down. Its tag format is [wave amp=50 freq=2][/wave]. amp controls how high and low the effect goes, and freq controls how fast the text goes up and down.

Tornado

../../_images/tornado.png

Tornao makes the text move around in a circle. Its tag format is [tornado radius=5 freq=2][/tornado]. radius is the radius of the circle that controls the offset, freq is how fast the text moves in a circle.

Shake

../../_images/shake.png

Shake makes the text shake. Its tag format is [shake rate=5 level=10][/shake]. rate controls how fast the text shakes, level controls how far the text is offset from the origin.

Fade

../../_images/fade.png

Fade creates a fade effect over the text that is not animated. Its tag format is [fade start=4 length=14][/fade]. start controls the starting position of the falloff relative to where the fade command is inserted, length controls over how many characters should the fade out take place.

Rainbow

../../_images/rainbow.png

Rainbow gives the text a rainbow color that changes over time. Its tag format is [rainbow freq=0.2 sat=10 val=20][/rainbow]. freq is the number of full rainbow cycles per second, sat is the saturation of the rainbow, val is the value of the rainbow.

Custom BBCode tags and text effects

You can extend the RichTextEffect resource type to create your own custom BBCode tags. You begin by extending the RichTextEffect resource type. Add the tool prefix to your GDScript file if you wish to have these custom effects run within the editor itself. The RichTextLabel does not need to have a script attached, nor does it need to be running in tool mode. The new effect will be activable in the Inspector through the Custom Effects property.

There is only one function that you need to extend: _process_custom_fx(char_fx). Optionally, you can also provide a custom BBCode identifier simply by adding a member name bbcode. The code will check the bbcode property automatically or will use the name of the file to determine what the BBCode tag should be.

_process_custom_fx

This is where the logic of each effect takes place and is called once per glyph during the draw phase of text rendering. This passes in a CharFXTransform object, which holds a few variables to control how the associated glyph is rendered:

  • identity specifies which custom effect is being processed. You should use that for code flow control.

  • outline is true if effect is called for drawing text outline.

  • range tells you how far into a given custom effect block you are in as an index.

  • elapsed_time is the total amount of time the text effect has been running.

  • visible will tell you whether the glyph is visible or not and will also allow you to hide a given portion of text.

  • offset is an offset position relative to where the given glyph should render under normal circumstances.

  • color is the color of a given glyph.

  • glyph_index and font is glyph being drawn and font data resource used to draw it.

  • Finally, env is a Dictionary of parameters assigned to a given custom effect. You can use get() with an optional default value to retrieve each parameter, if specified by the user. For example [custom_fx spread=0.5 color=#FFFF00]test[/custom_fx] would have a float spread and Color color parameters in its ` env` Dictionary. See below for more usage examples.

The last thing to note about this function is that it is necessary to return a boolean true value to verify that the effect processed correctly. This way, if there's a problem with rendering a given glyph, it will back out of rendering custom effects entirely until the user fixes whatever error cropped up in their custom effect logic.

Here are some examples of custom effects:

Ghost

tool
extends RichTextEffect
class_name RichTextGhost

# Syntax: [ghost freq=5.0 span=10.0][/ghost]

# Define the tag name.
var bbcode = "ghost"

func _process_custom_fx(char_fx):
    # Get parameters, or use the provided default value if missing.
    var speed = char_fx.env.get("freq", 5.0)
    var span = char_fx.env.get("span", 10.0)

    var alpha = sin(char_fx.elapsed_time * speed + (char_fx.absolute_index / span)) * 0.5 + 0.5
    char_fx.color.a = alpha
    return true

Pulse

tool
extends RichTextEffect
class_name RichTextPulse

# Syntax: [pulse color=#00FFAA height=0.0 freq=2.0][/pulse]

# Define the tag name.
var bbcode = "pulse"

func _process_custom_fx(char_fx):
    # Get parameters, or use the provided default value if missing.
    var color = char_fx.env.get("color", char_fx.color)
    var height = char_fx.env.get("height", 0.0)
    var freq = char_fx.env.get("freq", 2.0)

    var sined_time = (sin(char_fx.elapsed_time * freq) + 1.0) / 2.0
    var y_off = sined_time * height
    color.a = 1.0
    char_fx.color = char_fx.color.linear_interpolate(color, sined_time)
    char_fx.offset = Vector2(0, -1) * y_off
    return true

Matrix

tool
extends RichTextEffect
class_name RichTextMatrix

# Syntax: [matrix clean=2.0 dirty=1.0 span=50][/matrix]

# Define the tag name.
var bbcode = "matrix"

func _process_custom_fx(char_fx):
    # Get parameters, or use the provided default value if missing.
    var clear_time = char_fx.env.get("clean", 2.0)
    var dirty_time = char_fx.env.get("dirty", 1.0)
    var text_span = char_fx.env.get("span", 50)

    var matrix_time = fmod(char_fx.elapsed_time + (char_fx.range.x / float(text_span)), \
                           clear_time + dirty_time)

    matrix_time = 0.0 if matrix_time < clear_time else \
                  (matrix_time - clear_time) / dirty_time

    if matrix_time > 0.0:
        value = int(1 * matrix_time * (126 - 65))
        value %= (126 - 65)
        value += 65
    char_fx.glyph_index = TextServer.font_get_glyph_index(char_fx.font, value)
    return true

This will add a few new BBCode commands, which can be used like so:

[center][ghost]This is a custom [matrix]effect[/matrix][/ghost] made in
[pulse freq=5.0 height=2.0][pulse color=#00FFAA freq=2.0]GDScript[/pulse][/pulse].[/center]